1. Statement of the Technical Field
The inventive arrangements relate to radio receiving equipment and more particularly to methods and systems for improving performance of a radio receiver operating in an simulcast communication environment.
2. Description of the Related Art
Simulcast communication systems have a plurality of transmitters that simultaneously broadcast identical data signals at the same frequency. The transmitters are positioned at geographically diverse locations such that a desired transmitted signal coverage is provided throughout a particular geographical area. Simulcast systems are useful for ensuring that a mobile communication unit will be able to receive a transmitted signal anywhere within a large or irregularly shaped geographic area.
Simulcast communication systems can experience time delay interference issues due to the fact that multiple transmitters are transmitting on the same frequency. Delay spread is a key parameter of such interference. Delay spread is most problematic when signals having a similar signal strength are received from two or more transmitters that vary greatly in their distance from the receiving unit. The large difference in distance can cause the signals from each transmitter to be received at the radio at slightly different times. Problems with delay spread can cause bit error rates to increase, leading to poor communications quality.
In a simulcast communication system with substantial amounts of delay spread, a mobile radio unit needs to have a relatively large receive bandwidth to optimize performance. While improving delay spread performance, a large receive bandwidth will degrade the ability of the receiver to reject adjacent channel interference. Accordingly, designers generally will select the widest receiver filter bandwidth which will meet required specifications for adjacent channel rejection (ACR) and then accept the resulting delay spread capability of the radio.